The present study is concerned with the determination of the optimal shape for a package containing multiple heating elements.
The optimization tool has been developed based on the inverse heat transfer (IHT) approach, incorporating a direct problem
solver, a numerical grid generator, a direct-differentiation sensitivity analyzer, and the conjugate gradient method. Shape
design that leads to a specified outer surface temperature distribution is predicted by the approach. In this study, the effects
of internal heat generation on optimal shapes of the packagings have also been evaluated. Several practical cases with various
imbedded heating elements and thermal conditions are studied. Results show that the approach provides an efficient computer-aided
design scheme for the shape profile determination. 相似文献
The hetro-structured oxide thin films from metal fluorocomplex solution have been prepared by the liquid phase deposition (LPD) method. The Pt/Nb2O5 and Au/Nb2O5 composite films can be prepared from a mixed solution of niobium source, H3BO3, Pt(NH3)4Cl2 and HAuCl4 aqueous solutions under the ambient temperature and atmosphere. In the case of Au/SiO2 composite film, (NH4)2SiF6 solution is used as a mother solution. The Pt and Au ionic species are deposited in Nb2O5 and SiO2 matrices. They are reduced to their metallic state after treatment above 200 °C. The size of dispersed particles can be controlled by heat treatment temperature. It is also clear that, gold nanoparticles are also found to interact with SiO2, although the interaction is smaller than that with Nb2O5 showing the size of Au nanoparticles remain smaller in Nb2O5 that in SiO2. 相似文献
2-Pyridine sulfenyl chloride (PS-Cl) is a useful reagent for simultaneously deprotecting and activating the mercapto-group of cysteine and of cysteine-peptides preliminary to disufide-bond formation. The S-protecting groups that are amenable to this reaction include trityl, diphenylmethyl, acetamidomethyl, t-butyl, and t-butylsulfenyl. 相似文献
Angiotensin converting enzyme (ACE) inhibitors have recently gained attention as a new class of drug in the therapeutic management of glaucoma. However, the application of eye drops is limited because of their chemical instability in aqueous solutions. To overcome such a problem, cyclodextrins (CDs) were introduced to form inclusion complexes. Three ACE inhibitors, namely, captopril, quinapril and fosinopril (FOS), were chosen and the effect of CDs on their thermal stability in aqueous solutions was investigated. All three drugs formed inclusion complexes of 1:1 stoichiometry with all three natural CDs and the FOS/γCD inclusion complex possessed the highest stability constant, resulting in thermal stability enhancement. Furthermore, the addition of antioxidants could greatly enhance the thermal stability of FOS in the presence of γCD in aqueous solutions. The inclusion complex formation of FOS/γCD was further examined by computational and experimental characterizations. All these characterization results confirmed that FOS and γCD formed a true inclusion complex that provided drug stabilization in the aqueous eye drop medium.
The species Dracaena and Sansevieria, that are well-known for different uses in traditional medicines and as indoor ornamental plants with air purifying property, are rich sources of bioactive secondary metabolites. In fact, a wide variety of phytochemical constituents have been isolated so far from about seventeen species. This paper has reviewed the literature of about 180 steroidal saponins, isolated from Dracaena and Sansevieria species, as a basis for further studies. Saponins are among the most characteristic metabolites isolated from the two genera. They show a great variety in structural motifs and a wide range of biological activities, including anti-inflammatory, anti-microbial, anti-proliferative effects and, in most case, remarkable cytotoxic properties. 相似文献
The chemical synthesis of L -propargylglycine (L -Pra) and of various derivatives is described. The new amino acid is a starting material for carboranylalanine (Car) and for tritiated norleucine. 相似文献
The synthesis of a new, boron-containing analogue of phenylalanine is described. Carboranylalanine (Car) carries a 1,2-carborane cage in place of the benzene ring of phenylalanine. It is obtained by the reaction of derivatives of propargylglycine with decaborane. Possibilities of practical application derive from the facile neutron activation of boron nuclei with mass number 10. 相似文献